Overview
Group B was introduced by the FIA in 1982 as replacement for both Group 4 (modified grand touring) and Group 5 (touring prototypes) cars.
Group A referred to production-derived vehicles limited in terms of power, weight, allowed technology and overall cost. The base model had to be mass produced (5000 units/year) and had to have 4 seats. Group A was aimed at ensuring a large number of privately-owned entries in races.
By contrast, Group B had few restrictions on technology, design and the number of cars required for homologation to compete—200, less than other series. Weight was kept as low as possible, high-tech materials were permitted, and there were no restrictions on boost, resulting in the power output of the winning cars increasing from 250 hp in 1981, the year before Group B rules were introduced, to there being at least two cars producing in excess of 500 by 1986, the final year of Group B. In just 5 years, the power output of rally cars had more than doubled.
The category was aimed at car manufacturers by promising outright competition victories and the subsequent publicity opportunities without the need for an existing production model. There was also a Group C, which had a similarly lax approach to chassis and engine development, but with strict rules on overall weight and maximum fuel load.
Group B was initially a very successful concept, with many manufacturers joining the premier World Rally Championship, and increased spectator numbers. But the cost of competing quickly rose and the performance of the cars proved too much resulting in a series of fatal crashes. As a consequence Group B was canceled at the end of 1986 and Group A regulations became the standard for all cars until the advent of World Rally Cars in 1997.
In the following years Group B found a niche in the European Rallycross Championship, with cars such as the MG Metro 6R4 and the Ford RS200 competing as late as 1992. For 1993, the FIA replaced the Group B models with prototypes that had to be based on existing Group A cars, but still followed the spirit of Group B, with low weight, 4WD, high turbo boost pressure and staggering amounts of power.
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